The present invention relates to a magnetic ink medium and corresponding reading unit, and a method for using same, the magnetic ink medium being particularly useful as an identification code for documents and the like.
EP-A-0310707 filed on Dec. 20, 1987 discloses a magnetically detectable identification code which has a plurality of regions or bars with diversifiable magnetic intensity which are mutually divided by blank spaces.
Said regions have a different magnetic intensity due to magnetic oxide layers with different thicknesses in the direction which is perpendicular to the laying plane of these regions or possibly regions in which the density of the magnetic oxide is diversified, so as to have different magnetic intensities which can be sensed or detected by a magnetic read head which generates a signal, the duration whereof is a function of the width of the regions and of the blank spaces in the read direction and the amplitude whereof is a function of the intensity of the magnetic field generated by each of said regions.
Said identification code, which is applied inside documents, for example by applying it onto a strip of plastic material which is embedded into the document or can possibly be applied directly onto the document or product, has proven itself to be very valid, since it allows to have a wide range of readouts which are determined not just by the presence or not of the magnetic region but also by its intensity.
This kind of code has turned out to be further improvable so as to significantly increase its security in terms of not allowing its fraudulent reproduction.